Ship elevator, cradle, and dock.



E. L. BURWELL. SHIP ELEVATOR, CRADLE, AND DOCK. APPLICATION FILED APR.14, 1909.

Patented Apr. 19, 1910.

4 SHEETS-SHEET l.

E. L. BURWBLL. SHIP ELEVATOR, CRADLE, AND DOGK.. APPLICATION P'ILEDAPE.14, 1909.

4 SHEETS-SHEET 2.

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ANDREW I:v GRAHAM 50. PNOTO-UYNOGRAPNERS WASHINGTON. DV (1 E. L.BURWELL.

SHIP ELEVATOR, CRADLE, AND DOGK.

APPLICATION PILED.APR.14, 1909. Q55 1 3,0 Patented Apr. 19, 1910.

4 SHEETS-SHEET 3.

E. L. BURWELL.

SHIP ELEVATOR, CRADLE, AND DOCK.

APPLICATION FILED APR. 14, 1909.

Patented Apr. 19, 1910.

4 SHEETSSHEET 4.

ANDREW B GRAHAM 00 FNDTO-LYTHOGRAPHERS. wAsmNe'mN. u. c

NET

STATS EDWARD L. BURWELL, OF WINCHESTER, MASSACHUSETTS.

SHIP ELEVATOR, CRADLE, AND DOCK.

Specification of Letters Patent.

Patented Apr. 19, 1910.

Application filed April 14, 1909. Serial No. 489,930.

To all whom it may concern:

Be it known that I, EDWARD L. BURWELL, a citizen of the United States,and resident of \Vinchester, county of Middlesex, State ofMassachusetts, have invented an Imrovement in Ship Elevators, Cradles,and l ocks, of which the following description, in connection with theaccompanying drawing, is a specification, like characters on the drawingrepresenting like parts.

This invention applies to marine railways in general, and it has for itsobject the production of novel means for docking, cradling and elevatinga ship or other vessel from the dock to the land, whereby the vessel maybe moved bodily to another point for examination, repairs, etc.

My invention is designed for handling vessels of any size, up to thelargest, with great facility at a relatively small expenditure of power,and wlth entire safety to the vessel and contents, and the capacity ofan apparatus embodying my invention depends wholly upon the requirementsof any particular locality.

In its general features my invention comprehends a dock or basin solocated as to have suificicnt depth of water to float a vessel at lowtide, in which dock or basin is installed an elevator of adequatedimensions and strength to support and raise a vessel, and her cargo ifnecessary, from her position afloat in the dock, the elevator havingmovable upon it longitudinally a cradle of special construction. Thiscradle is arranged to travel upon a series of tracks on the elevatorplatform, and has mounted upon it means adapted to cooperate with thesides and bilges of the vessel to sustain the latter in upright positionon suitable keelblocks when the cradle and elevator are lifted to removethe vessel from the water. The weight of the elevator and cradle iscompensated or counterbalanced by suitable weights, and the additionalload or weight of the vessel and her contents is taken care of by asystem of weight units so applied to the elevator and the parts carriedthereby as to render the elevation thereof a very simple matter, as willappear hereinafter. As an additional elevating means I prefer to employhydraulic or other power, applied to the elevator from beneath as hereinshown, whereby the raising and lowering of the elevator and partsthereon can be controlled with great accuracy and very readily.

When the properly cradled vessel has been raised upon the elevator tothe shore level the cradle can be run ofi from the elevator trackseither directly to a corresponding set of tracks on shore, or onto aplatform-car of suitable construction, arranged to run on fixed tracksto any suitable destination. The arrangement of shore tracks may bevaried in many ways, as will be obvious, such arrangement depending uponthe desired disposition of the vessel after it has been elevated fromthe dock to the proper level for removal from the elevator.

The various novel features of my invention will be fullydescribed in thesubjoined specification and particularly pointed out in the followingclaims.

Figure 1 is a view in elevation of an apparatus embodying my presentinvention, viewed from the inlet or entrance end of the dock or basinand showing the elevator and cradle in readiness to be raised, a vesselin outline being shown on the cradle and held in upright positionthereon; Fig. 2 is a top plan view of the apparatus shown in Fig. 1, thesides and inner end of the dock being broken off to save space; Fig. 3is an enlarged end elevation of the cradle and the means thereon forsupporting the vessel in upright position, the supporting means at oneside of the vessel being shown in operative position, while thesupporting means on the opposite side is in inoperative position; Fig. 4is a detail in side elevation and enlarged of two of the elevatorlifting units, to more clearly show their construction; Fig. 5 is a topplan view thereof; Fig. 6 is a detail of a brake mechanism forregulating the vertical movement of the elevator; Fig. 7 is a viewsimilar to Fig. 3, but showing a diiferent form of support on the cradlefor cooperating with the vessel; Fig. 8 is a detail view of the lowerpart of one of the flexible members or slings adapted to engage theunder-body of the vessel.

Referring to Figs. 1 and 2, I have shown a preferably rectangular dock Ainclosed on two of its sides by a concrete or other suitable strong andsolid structure as at A, the inner end of the dock or basin being closedby a transverse wall A The outer end of the dock or basin is open, andthe floor thereof is at such a level, and the dock is so located, thatat low tide a vessel may be floated into the dock. The particular construction of the dock or its dimensions are of no particular moment sofar as my invention is concerned, the dock being made of the properdimensions to admit a vessel of large or small size. Within the dock andvertically movable therein 1 install an elevator of suitable dimensionsand strength, and as herein shown the elevator in general comprises aplatform E stiffened and braced at E as may be necessary to secure therequisite rigidity and strength, it being understood that the elevatormust be capable of sustaining and lifting a cradle and a vessel on thecradle. Suitable guide-rolls E l and 2, are carried by the elevator totravel along the vertical side walls of the dock or basin, and as shownin Fig. 2, I prefer to have a series of such guiderolls at each side ofthe elevator. Longi tudinal ails E are fixed on the elevator platform D,said rails running from end to end of the platform and adapted toregister with corresponding rails leading from the inner end of the dockwhen the elevator platform is raised to its discharging height. Fixedstops E are secured in the side walls A to overhang the sides of andengage the elevator platform when at discharging level, to preventfurther upward movement thereof. Upon the series of parallel tracks E onthe elevator, I mount a cradle shown separately in Fig. 8, the cradlebeing built of structural steel or other desired material, suitablybraced and stiffened in various di rections, and comprising in endelevation a truss consisting of a horizontal member C, and upperinclined members C, the bottom member being provided with series oftruck wheels C to travel on the tracks F and A". Along the central lineof the cradle I provide keel-blocks, as c F 3, upon which the keel V ofa vessel is to rest, the hull of a vessel being indicated at V in Figs.1, 2, 3 and 7. l have mounted upon the cradle two opposed series ofsupports arranged on opposite sides of the line of heelblocks, and inFigs. 1, 2 and 3, each support consists of a tower-like structure D,preferably built of steel and suitably braced and having its base Dprovided with wheels (Z arranged to travel on tracks (Z laid upon thesloping members C of the cradle, right angles to the length of thelatter, as clearly shown in Figs. 2' and 3. As the several sets oftracks incline outwardly and downwardly from the center of the cradle,the upright supports D will tend to move outward to aid the sides of thecradle, and they may be stopped or locked at different points alongtheir respective paths of movement in any suitable manner. Herein,referring to Fig. 3, 1 have shown the base of support: as provided witha locking dog (Z arranged to cooperate with a rack cl see Fig. 2 ar'anged adjacent a pair of tracks or rails cl. The supports D extendupward from the cradle high enough to have their upper ends well abovethe upper deck of the largest vessel, which may be handled by a givenstructure, and these supports are also of sufficient height that theirupper ends will always be above the water level, indicated at L, Fig. 1,no matter if the elevator is atits lowest posit-ion. On a suitableplatform D on the top of each support, I provide a power mechanismindicated in general. at M, and preferably electric power will beadvised on account of the great convenience thereof, and its ready meansof installation. Along the inner faces of each support, I

prefer to provide a series of contact rolls a one or more of which maybe brought into engagement with the sides of a vessel when the supportsare in their operative position. I also provide guide sheave a? on eachsupport over which travels a flexible member or sling d attached at itslower inner end to the cradle adjacent its center line, and ifconvenient to the keel-blocks c, as herein shown. Each one of theseslings (Z is carried upward from the guide sheaves (7 to the powermechanism M which latter will include a suitable winding drum by meansof which the sling may be drawn taut.

Referring to the right hand support D in Fig. 3, it will be seen that itis in inoperative position, and that its sling d hangs slack, thesupport D being some distance from the side of the vessel V. N ow byoperating the mechanism M, the sling d is gradually tightened and as itis tightened it will cause the support to travel inward and up alongrails (Z until the sling is drawn tant in engagement with the bilge ofthe vessel, and one or more of the rolls (Z will be brought intosupporting engagement with the sides of the vessel, as shown at the leftin Fig. where the support and its sling are shown as properlycooperating with the vessel to hold the latter in upright position.

In Fig. l and also in Fig. 2 the several supports D are shown asproperly cooperating with the vessel to support the same in an uprightposition on the cradle and by aranging a sufficient number of supportsand providing for their requisite strength a vessel of any size, with orwithout a cargo, will be promptly, securely and safely held in uprightposition on the cradle, even after the elevator has raised the latterand the vcsse out of the water in the dock.

lslanifestly the dead weight of the ele vator, the cradle thereon, andthe supports will be large if the plantis designed to handle largevessels, and I ave compensated for or counterbalanced the dead weight ofthe elevator and cradle, as will be presently explained.

Un the dock at each side thereof, 1 provide a superstructure of anysuitable character and construction, and comprising essentially verticalmembers G and outwardly and downwardly inclined members G, which latterare cross braced at g, Fig. 2, to give-the necessary rigidity, themembers G being shown as arranged in pairs, see Fig. 2, and at theirlower ends entering chambers A in the structure of the dock. Thesuperstructure is provided with guidesheaves 9 over which are ledcounterbalancing cables g secured at their lower ends to the sides ofthe elevator, the upper ends of the said cables having attached weightsG, see Fig. 1, the sheaves being located high enough on thesuperstructures so that when the elevator is in its highest position,there will be ample room for the travel of the weights G Thesecounterbalancing weights in the aggregate are sufficiently heavy topractically counterbalance the dead weight of the elevator, cradle andsupports thereon, so that when the cradle is empty the elevator can beraised or lowered with a relatively slight expenditure of power. At thetop of each superstructure, 1 have mounted in suitable bearings G aheavy horizontal shaft G the two shafts being arranged in parallelism,Figs. 1 and 9., above and near the plane of each side wall of the dock.Each shaft has rigidly attached to it a series of heavy sheaves G and asshown in Fig. 2, each sheave is located midway between the adjacent pairof inclined members G, the latter acting as guide-ways for gravityactuated lifting units to be hereinafter described. Strong chains orcables G are attached to the elevator platform and are carried up aroundthe sheaves G and outward and downward therefrom, as best shown in Fig.1, and a lifting unit 1V is suitably attached to the free end of each ofsuch lifting cables G By inspecting Fig. 2, it will be seen that 1 haveshown three sheaves GR on each of the shafts G for convenience, but itis to be understood that I may use any suitable number of sheaves andlifting cables according to the desired capacity for the dock and theprobable weight to be raised by the elevator. These gravity-actuatedlifting units may be variously constructed, provided they are arrangedto travel upon the inclined supporting members G of the superstructureand are relatively compact when compared with weight. Herein Thave shownthem as box-like in structure, in practice made of iron or steel, andprovided with suitable wheels 20 to travel upon the guideways providedby the members G, and save that preferably the lifting cables G may haveeach a permanently attached lifting unit TV, all of the units aresubstantially alike. For convenience, however, the other units areindicated by W in the drawings, and the bottom of each is shown in Fig.a as provided with a hook to, while coupling hooks 4.0 on the sides andupper end of the body of each unit are adapted to engage lugs 10 on thesides and at the lower end of the body of the next unit ahead. As shownin Figs. 1 and 4: the front and rear ends of the body are vertical, andthe body is closed at the top, with a hopper-like inlet to for theintroduction of water or other heavy body, and a valved outlet e0 isprovided near the bottom and rear or lower end of the body, by which thecontents if liquid can be discharged.

Any suitable coupling device may be used for connecting one unit withanother, in a series or train of varying numbers, and it will beunderstood that preferably the separate units WV are drawn up theinclined guide-ways G and coupled onto one another and to the units Wpermanently attached to the lifting cables, until a sufficient number ofunits acting cumulatively will be sufficient to raise the elevator andits load. If tankcar units are employed, such as illustrated herein,they may be connected in series with the lifting cables while theelevator is at its lowest point, and then filled with water by means ofsuitable filling nozzles N connected with standpipes N carried alongsidethe guide-ways G, the nozzles overhanging the latter and properly spacedto empty into the hopper-like inlets 10 By this arrangement the emptyunit-s are hauled up into position, coupled together, and then filled orloaded to bring them up to weight, and a very uniform lifting actionwill thereby be exerted upon the elevator through all the lifting cablesG On the other hand the units may be filled before they are hauled up toposition, or the permanent weight of each unit may be constant, as wouldbe the case were the box-bodies herein shown filled with sand, slag,etc. In either case the power required for positioning the units need bebut little greater than that sufficient to haul a single unit up theinclined guide-way, and in Fig. 1 I have shown one arrangement ofhauling mechanism.

On the upper end of each guide-way G I mount a sheave 10, over which iscarried a wire rope or cable w having at its free end a loop or eye waFig. 4, adapted to engage the hook to on one of the units W The otherend of the cable is brought down to an electric or other hoisting engineTV on the top of the dock structure, by means of which the units aredrawn up out of the chambers or recesses A into position to be connectedwith the elevator-lifting cables G By means of a relatively low-poweredhoisting mechanism one after another of the lifting units is drawn upinto operative position and connected with its proper cable, as shown inthe drawings, until the combined weight of all the units issubstantially sufiicient to raise the load on the counterbalancedelevator and cradle, such parts being shown in Fig. 1 in readiness to beraised. The ele vator and cradle being counterbalanced the principalfunction of the lifting means, to wit: the cumulativelyacting gravityactuated units, is to compensate for the weight of and lift the vesseland contents. While this lifting could be performed wholly by the units,by adding a sufiicient number, I prefer to use in connection therewithauxiliary lifting means, such as a piston 72, Fig. 1, vertically movablein a cylinder 79 embed ded in the bottom of the dock, and controlled bya hydraulic or pneumatic motor P. In practice, with large elevators amunber of these auxiliary lifting devices would be employed, and as theentire load to be lifted is practically counterbalanced a relativelyslight expenditure of power is required in the auxiliary means.

. ly the apparatus described the elevator is raised to bring its railsor tracks E to the level of the tracks A at the top of the dock, andwhen so raised the cradle and the vessel supported thereon can be runelf onto the tracks IV and conveyed to any desired point, in a mannersimilar to that employed in marine railways at present. Inasmuch as thetransportation of the cradle and the vessel supported thereon may beeffected in various ways after the vessel has been raised from the deckI have only shown one form, viz: the tracks A as sutlicientlyillustrative of such transportation.

The auxiliary lifting means is brought into action when the vessel isafloat in the dock above the cradle, for by such means the elevator andcradle are raised from their lowest position into place for the cradleto receive upon it the vessel V, as shown in Fig. 1.

lt desirable to have means for readily controlling the vertical movementof the loaded elevator, and for this purpose I have mountedln'ake-sheaves 2, Figs. 2 and 6, on the overhead shafts G embraced bybrake or friction shoes 3, fast at one end and at the other endsconnected with levers 4 operated by compressed air, hydraulic or otherbrake cylinders 5, preferably connected in practice with a centralcontrol station, so that the rotation of the shafts G may be easily andproperly governed.

The flexible members or slings by which the under-body of the vessel issupported mav be divided at their lower or inner ends into a pluralityof members d, Fig. 8, con- 11 cted at their lower ends tothe keel-blocks(1 and converging to common connection rZ", so as to present afairshaped sling. This is of advantage as thereby the action of eachsling is distributed for a considerable distance along the bilges of thevessel, to better and more securely support the latter in uprightposition on the cradle.

Inasmuch as the adjustment and movement of the upright supports D on theeradle, Fig. 3, will be effected while the lower portions of suchsupports are under water, I have provided the locking dogs or devices (Zwith releasing links or rods (Z which extend up to the platform I) andfrom which the dogs are operated to release them from the racks (P, Fig.2.

Referring to Fig. 7 I have shown a modified form of supporting means onthe cradle, wherein upright columns or towers ll are fixedly attached tothe cradle at intervals along its sides, each tower having a platform 1with a hoisting motor P thereon. A derrick-arm R is pivoted at its feetat R at the base of each tower and is inclined toward the center of thecradle, and adjusted as to its inclination by suitable tackle It. Slings(N, such as shown in Fig. 8, are provided, the connections d thereofhaving each an attached block J, through which is reeved a cable (Wpassing over sheaves (Z on the arm R and led thence to the motor R.After proper adjustment of the supporting arms R according to the widthof the vessel the slack of the cables (5 is taken up and the slings (Ware thereby drawn up taut around the sides and bilges of the vessel, asin Fig. 7, and the vessel is thereby securely held in upright positionon the cradle, and thereafter it can be lifted out of the deck by theelevator as has been described.

The operation of the apparatus as a whole will be manifest from thedetailed description previously set forth and need not be repeated, butit may be stated that when a vessel is to be returned to the dock andagain floated the cradle supporting the vessel will be run onto thelifted elevator, and the lat ter will be then lowered. Such lowering iseffected by disconnecting a sufficient numb r of the lifting units fromthe lifting cables to enable the weight of the vessel and contents tocause the elevator to descend, and when the vessel is at flotationheight in the water in the deck the cradle supports are cast off, andthen the elevator and cradle are again made to descend far enough toallow the vessel to clear the cradle. The vessel can then be floated outof the dock and the apparatus is in readiness for the next vessel toenter.

lVhile the control of the elevator in its vertical movement can beattained by the addition or removal of the lifting units, thus utilizinggravity alone, it will in most cases probably be preferable to employ inconnection therewith the auxiliary lifting means hereinbefore referredto.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is 1. In apparatus of the class described, anelevator, a cradle longitudinally movable thereon, means tocounterbalance the weight of the elevator and cradle, means mounted onthe cradle to engage and support a vessel and maintain it upright on thecradle, and a system of lifting weights adapted to be connectedindividually with and to act cumulatively upon the elevator and the loadthereon, to raise the same to the desired level.

2. In apparatus of the class described, a counterbalanced elevator andcradle, the latter movable longitudinally on the former, means on thecradle laterally movable to ward and from a vessel thereon, to maintainthe vessel upright on the cradle, and means to govern the elevation anddescent of the elevator and its load, said means including a system ofweight units adapted to be brought singly into cooperation with theelevator, to act cumulatively thereupon.

3. In apparatus of the class described, an elevator, a cradlelongitudinally movable thereon and provided with means to engage andsupport in upright position a vessel on the cradle, and means to raisethe elevator and its load, said means including a plurality of weightunits adapted to be brought singly into cooperation with the elevator toact cumulatively thereupon.

4;. In apparatus of the class described, an elevator, means carriedthereby to support a vessel in upright position, and means to raise theelevator and its load, said means including a series of overhead liftingcables connected with the elevator, and weight units adapted to beattached one after another in series to said cables to act cumulativelyupon and lift the elevator and its load.

5. In apparatus of the class described, an elevator, means carriedthereby to support a vessel in upright position, and means to raise theelevator and its load, said means including a plurality of series ofseparable weight units adapted to be brought singly into cooperationwith the elevator to act cumulatively thereupon.

6. In apparatus of the class described, an elevator, means carriedthereby to support a vessel in upright position, and means to raise theelevator and its load, said means including a plurality of separateweight units, and a device to bring such units one after an.- other intocooperation with and to act onmulatively upon the elevator.

7. In apparatus of the class described, a dock or basin into which avessel can be floated, an elevator vertically movable in the dock, acradle on the elevator to support and maintain upright a vessel thereon,and means to raise the elevator and its load to a predetermined height,said means including a plurality of separate lifting weights adapted tobe brought in varying number into cooperation with the elevator to actcumulatively upon and lift the elevator and its load.

8. In apparatus of the class described, a

dock or basin 1nto which a vessel can be floated, an elevator verticallymovable in the dock, a cradle on the elevator to support and maintainupright a vessel thereon, counterbalancing means for the elevator andcradle, and means to raise the elevator and its load to a predeterminedheight, said means including a plurality of separate lifting weightsadapted to be brought in varying number into cooperation. with theelevator to act cumulatively upon and lift the elevator and its load.

9. In apparatus of the class described, a dock or basin into which avessel can be floated, an elevator vertically movable in the dock, acradle on the elevator to support and maintain upright a vessel thereon,and means to raise the elevator and its load to a predetermined height,said means including a plurality of gravity-actuated lifting unitsadapted to be operatively connected in varying number with the elevatorto act cumulatively thereupon.

10. In apparatus of the class described, a dock or basin for thereception of a vessel, an elevator in said dock and vertically movabletherein, a cradle mounted on the elevator and adapted to be movedlongitudinally thereof, means on the cradle to sustain a vessel inupright position thereon, means to counterbalance the weight of theelevator and cradle, an over-head shaft above and at each side of thedock, a series of sheaves on each shaft, an inclined track leadingdownward from each sheave, lifting cables connected with the elevatorand carried up over the sheaves, a series of lifting units adapted totravel on each track and to be connected in varying number with theupper end of each cable, and means to raise said lifting units singly tobe connected with a cable.

11. In apparatus of the class described, a dock or basin for thereception of a vessel, an elevator in said dock and vertically movabletherein, a cradle mounted on the elevator and adapted to be movedlongitudinally thereof, means on the cradle to sustain a vessel inupright position thereon, means to counterbalance the weight of theelevator and cradle, an over-head shaft above and at each side of thedock, a series of sheaves on each shaft, lifting cables connected withthe elevator and carried up over the sheaves, and means to connectlifting weights in requisite amount to the free ends of the cables toeifect lifting of the elevator and its load by cumulative action of theweights.

12. In apparatus of the class described, a dock or basin for thereception of a vessel, an elevator in said dock and vertically movabletherein, a cradle mounted on the elevator and adapted to be movedlongitudinally thereof, means on the cradle to sustain a vessel inupright position thereon, counterbalancing means for the dead weight ofelevator and cradle, a series of sheaves rotatably supported above thedock at each side thereof, lifting cables attached to the elevator andcarried up over said sheaves, a plurality of separate lifting unitsadapt-ed to be coupled together in series and connected with the free enls of said cables, to act cumulatively upon and raise the elevator andits load, and means to bring the lifting units into cooperation with thecables.

13. In apparatus of the class described, a dock into which a vessel maybe floated, a vertically movable elevator in the dock and provided withlongitudinal rails, a cradle provided with trucks to travel on the railsand move longitudinally off the elevator, means on the cradle to supporta vessel thereon, a superstructure at each side of the dock and eachprovided with a series of sheaves, lifting cables attached to the sidesof the elevator and carried up over the sheaves, downwardly andoutwardly inclined guideways adjacent each sheave and mounted on thesuperstructure, separate gravity acting lifting units adapted to traveon the guideviays and to be connected in varying number with the upperend of each lifting cable whereby the cumulative action of all of theconnected units will operate to lift the elevator and its load, means tobring said units into cooperation with the lifting cables, and brakemechanism to control the lifting action.

l l. In apparatus of the class described, a dock into which a vessel maybe floated, a vertically movable elevator in said deck, a cradlelongitudinally movable on the elevator and provided with means tosustain a vessel in upright position, counterbalai'icing means for thedead weight of the elevator and cradle, parallel over-head shaftssupported above the dock at each side thereof, a series of sheaves faston each shaft, lifting cables attached to the sides of the elevator andcarried up over the sheaves, and means to apply to the upper free end ofeach cable a variable lifting weight, and brake mechanism to control therotation of the over head shafts during vertical movement of theelevator and its load.

15. In apparatus of the class described, a dock into which a vessel maybe floated, an elevator vertically movable in the dock, a cradle carriedby the elevator and provided. with means to sustain a vessel in uprightposition on the cradle, parallel over-head shafts mounted above and atthe sides of the dock and each provided with a series of sheaves,lifting cables attached to the sides of the elevator and carried upwardover the sheaves, downwardly and outwardly inclined guideways adjacentsaid sheaves, separable weight units adapted to travel along theguideways and to be connected in varying number with the upper end ofeach lifting cable, and means to raise said weight I l i l i l l I l l il i ,l l l l J l l l I l units individually and operatively connect themwith the cables, the cumulative action of the units connected with eachcable operating to overcome the weight of the eleva tor and its load.

16. In apparatus of the class described, a dock into which a vessel maybe floated, an elevator vertically movable in the dock, a cradle carriedby the elevator and provided with means to sustain a vessel in uprightposition on the cradle, parallel over-head shafts mounted above and atthe sides of the dock, and each provided with a series of sheaves,lifting cables attached. to the sides of the elevator and carried upwardover the sheaves, downwardly and outwardly inclined guide ways adjacentsaid sheaves, separable weight units adapted to travel along the guide'ays and to be connected in varying number with the upper end of eachlifting cable, and means to raise said weight units individually andoperativcly connect them with the cables,

the cumulative action of the units connected with each cable operatingto overcome the wei ht of the elevator and its load, combined with anauxiliary lifting device to act upon the elevator and its loadindependently of the action of said weight units.

17. In apparatus of the class described, a dock into which a vessel maybe floated, an elevator vertically movable in said dock, means to guidethe elevator in such movement, stops to limit the rise of the elevator,a cradle carried by the elevator and adapted to be moved therefrom whenthe elevator is raised, means on the cradle to sustain a vessel inupright position thereon, lifting means to raise the elevator and bringthe cradle into position beneath a vessel floating in the dock, andother means to act upon and raise the elevator and its load to thedesired level, said other means including a plurality of gravityactuated lifting members adapted to be operatively connected in varyingnumber with the elevator, toe cumulative action of said lifting memberserving to lift the elevator and its lead.

18. In apparatus of the class described, a dock into which a vessel maybe floated, an elevator rtically movable in the dock, a cradlelongitudinally movable on the elevator and provided with means tosustain a vessel in upright position on the cradle, counterbalancingmeans for the dead weight of the elevator and cradle, lifting cablesattached to the elevator, over-head sheaves around which the said cablesare carried, downwardly and outwardly inclined tracks adjacent thesheaves, gravity actuated lifting members adapted to be connected withthe free end of each cable, each of said members having a hollow bodyand wheels to travel on the tracks, means to fill the bodies of saidmembers with a weighty material,

and power mechanism adapted to be temllo porarily attached to one afteranother of said gravity actuated members to raise them along the tracksinto position to be operatively connected with a cable.

19. In apparatus of the class described, a cradle having uprightsupports arranged in two opposed series, means to move the supportstoward and from a vessel between the two series, and flexible membersconnecting said supports and the cradle along the longitudinal centerthereof, to contact with the sides and bilges of a vessel and maintainthe latter in upright position.

20. In apparatus of the class described, a cradle having transverseseries of tracks sloping from the center toward the sides of the cradle,supports movable on said tracks toward and from the center line of thecradle, said supports being arranged in two opposed series to receive avessel between them, flexible members connecting the said supports andthe center of the cradle, and means to tighten said members, whereby thesupports will be moved inward into engage ment with the sides of thevessel and the flexible members will contact with and conform to thebilges thereof.

21. In apparatus of the class described, a cradle having a central rowof keel-blocks, a series of upright supports on the cradle at oppositesides of the keel-blocks, flexible members attached at their lower endsto the keel-blocks and connected at their other ends with the supports,and means to draw said members taut in engagement with the bilges of avessel resting on the keel-blocks, to maintain the vessel in uprightposition on the cradle.

22. In apparatus of the class described, a cradle, opposite series ofupright supports mounted thereon and extending longitudinally of thecradle, said supports being movable toward and from a vessel resting onthe cradle between the two series, slings attached to the cradleadjacent its center line and leading therefrom to the supports,

and means to draw said members taut against the underbody of the vesselto serve as supporting slings therefor and maintain it upright on thecradle.

28. In apparatus of the class described, a cradle, opposite series ofupright supports mounted thereon and extending longitudinally of thecradle, said supports being individually adjustable with relation to thecenter line of the cradle, a sling connecting each support and thecradle, each sling comprising a plurality of members attached to thecradle adjacent its center line and converging to a common connection attheir outer ends, and means to draw taut the slings about the underbodyof a vessel.

24L. In apparatus of the class described, a cradle, upright supportsthereon in two series on opposite sides of its center line and movabletoward and from such center line, a sling connected with each supportand extended downward and inward therefrom, each sling having aplurality of diverging members at its lower end fixedly attached to thecradle adjacent its longitudinal center, and means to draw the slingstaut about the underbody of a vessel on the cradle.

25. In apparatus of the class described, a cradle, upright supportsthereon in two series on opposite sides of its center line, transversetracks on which the supports are movable, slings attached to the cradleadjacent its center line and leading therefrom to the supports, andmeans to tighten the slings and thereby draw them and the supports intosupporting engagement with a vessel on the cradle.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

EDWARD L. BURIVELL.

Witnesses JOHN C. EDUARDS, THOMAS J. DRUMMOND.

